In modern automotive engines fuel management is accomplished by use of electrically controlled fuel injectors that spray fuel into the air/fuel induction system. The injectors are operated for short periods of time that are determined by a system of sensors and usually a computer which responds to the sensed information and appropriately operates the injectors. It is common practice to have fuel pressure applied to the injectors continuously so that the fuel is controlled at the injectors. It is necessary that the fuel available at the injectors be maintained at a stable pressure and flow availability so that additional sensors of fuel pressure are not required at the injectors to maintain good control of the amount of fuel flowing through an injector when the injector is opened. It is also important that the valve portions of the injector stay wet with fuel to prevent drying of the seals and to lubricate the injector mechanical structure.
The concept disclosed herein provides a means by which these requirements are met by using a module that is remotely mounted away from the injectors such that fuel inlet and outlet passages and the electrical control wiring are contained in leads that communicate from this module to each injector. The module, being remotely mounted, may be in an environment that is more tolerant with regard to temperature and vibration for the electrical and fuel pressure management functions. Additionally, the module may be constructed of plastic materials to lower the cost, provide a single device for testing and qualification prior to installation, and provide a fuel reservoir means, by virtue of the leads, where the injectors are always "wet". Since only small diameter leads communicate between the module and the injectors, packaging of the fuel and air induction systems are simplified, and the reduced mass of the system mounted on the engine reduces failures associated with accelerations of the mass mounted on the engine. Remotely mounting the module also facilitates the prevention of air entrapment causing air pockets that may travel to the injectors, or prevent proper regulation of the fuel pressure. This is easily accomplished in a module environment manifolds, communicated by a passage and orifice which allows by constructing two air entrained or trapped in the fuel source portion to bleed directly into the return line on the downstream return side of a fuel pressure regulator mounted in the return manifold which maintains pressure applied to the injectors. Since the fuel flow is much greater than the actual fuel use in these systems, this continuous bleeding orifice which passes little fuel but a lot of air does not adversely affect fuel system pressure unless a large volume of air arrives at the bleed point. In any case, the adverse effect is much less than having this air trapped in a fuel rail. The remotely mounted module also provides convenient connections of lines from the tank which may be of a lower temperature resistance less costly material. Also, if desired a filter may be combined with the module for easy servicing.
In practice such a module has many benefits for the user:
(a) A single fuel management device which is easily qualified electrically and for fuel pressure. PA0 (b) The ability to easily deal with entrained air. PA0 (c) Ease and reliability of connecting fuel and electrical junctions to the injectors that have been adapted to this type system. PA0 (d) More flexibility in air/fuel induction systems to the engine, less space required, few constraints in design, optimized location and aiming of injectors. PA0 (e) Standardization of many components of the present system that leads to lower cost and better reliability. PA0 (f) Reduction of assembly time, improved assembly reliability. PA0 (g) Improved diagnostics and repairing capabilites, remove and replace one device. PA0 (h) A system which is "fail safe" from a fuel connection standpoint, check valves at outlets are pressure manifold injector connections. PA0 (i) In car fuel system pressure check without injector leakage. PA0 (j) Individual injectors are easily checked or replaced. PA0 (1) Easily connected by the leads from the module. PA0 (2) Easily individually secured to the intake manifold.